Life cycle assessment of carbon and energy balances in jatropha production systems of burkina faso

Zentrum für Entwicklungsforschung
_______________________________________________________________

Life cycle assessment of carbon and energy balances in
Jatropha production systems of Burkina Faso

Inaugural-Dissertation
zur
Erlangung des Grades
Doktor der Agrarwissenschaften
(Dr. agr.)

der Hohen Landwirtschaftlichen Fakultät
der
Rheinischen Friedrich-Wilhelms-Universität
zu Bonn

von
SOPHIA EMILIA BAUMERT
aus
BERLIN


1. Referent: Prof. Dr. Asia Khamzina
2. Referent: Prof. Dr. P. L. G. Vlek
Tag der Promotion: 10.01.2014
Erscheinungsjahr: 2014
Diese Dissertation ist auf dem Hochschulschriftenserver der ULB Bonn
elektronisch publiziert

ABSTRACT


ModernbioenergyoffersseveraladvantagestoBurkinaFaso,acountrythatisheavily
dependent on imported fossil fuel and greatly relying on traditional biomass use. In
this context, Jatropha curcas has been recently introduced as a lowͲmaintenance
energycropwiththepotentialtoincreaseenergysecuritywhilecontributingtoland
rehabilitationandclimatechangemitigation.ThisstudyidentifiedJ.curcascultivation
systemspracticedinBurkinaFasoandanalyzedtheirbiomassdynamicsandcarbon(C)
accrualovertimeaswellassoilͲCstocks.Thesedata,togetherwiththeinformationon
J. curcas seed transformation processes, were integrated in a life cycle assessment
(LCA) of the greenhouse gas (GHG) emission and energyͲsaving potential of the
completebiofuelproductionpathways.
The studied J. curcas systems include interplanting with annual crops,
intenselymanagedplantations,afforestationofmarginalland,plantingsalongcontour
stone walls, and traditional living fences. Destructive aboveͲ and belowͲground
biomassdeterminationenabledtheidentificationofgrowthstagesanddevelopment
ofallometricequationsrelatingtotalshootandrootbiomasswiththestemdiameter
thatshowedverygoodfits(R²>0.9).Empiricalgrowthmodelsrelatedwoodybiomass
andtreeagebyathreeͲparametricnonͲlinearlogisticfunction.Accordingtothemodel
results,thebiomassproductionofJ.curcasplantspeakedbetweenthe10thand15th
year after planting, with intercropping and intensely managed systems showing the
highest stock (21 t haͲ1). Afforestation systems on marginal land had the lowest
biomassstocks(<0.1thaͲ1),andcouldnotbemodeledduetodrasticmortalityatan
earlyageintheabsenceofmaintenance.Soilanalysisdidnotrevealacleartrendof
soilorganiccarbon(SOC)dynamicsovertimewhencomparingthesoilcarbonstatusin
4ͲyearͲold J. curcas sites with that in the reference cropland. Only J. curcas living
fences exhibited significantly higher SOC stocks in the top 20 cm soil based on a
chronosequencestudycovering20yearsofJ.curcascultivation.
All J. curcas production pathways showed GHG emission reductions and

energy savings of up to 82% and 85%, respectively, as opposed to fossil fuel.
Decentralized production of straight vegetable oil and its consumption in stationary
diesel engines showed the best performance. However, J. curcas plantation systems
hadverylowlandͲuseefficiency(6.5Ͳ9.5GJhaͲ1)andthusahighlandͲusereplacement
potential.CarbonͲstockgainswereattainedwhenintroducingJ.curcasoncroplands.
However,thedisplacementofagriculturalactivitiestootherareascanindirectlyresult
in C losses. Human energy accounted for 24% of the total energy balance, indicating
highmanuallaborrequirementsinsmallͲscaleJ.curcassystems.Monetaryvaluationof
CoffsetsviacarbontradingschemesshowedreturnsbelowUS$350over20years.
Overall, J. curcas biofuel production can contribute to climate change
mitigation and national energy independency. However, due to low landͲuse
efficiency,highlaborrequirementsandtheunsuccessfulcultivationonmarginalland,
J. curcas becomes a direct competitor with food crops and is a not viable option for
smallholder farmers. Whereas J. curcas cultivation is yet to be intensified through
improvedplantmaterialandoptimizedagronomicmanagement,thetraditionalhedge
systemsareapreferableoptionforseedproductionastheyofferadditionalbenefitsof
erosioncontrolandfieldprotectiontofarmers’fields.


Analyseducycledevieducarboneetdel’énergiedanslessystèmesde
laproductiondeJatrophaauBurkinaFaso



RESUME


Les bioénergies modernes présentent plusieurs avantages pour le Burkina Faso, un
pays fortement dépendant des hydrocarbures importés et s’appuyant largement sur
l’utilisation traditionnelle de la biomasse. Dans ce contexte, le Jatropha curcas est

devenupopulaire,réputécommeunecultureénergétiquedemandantpeudesoinset
ayantlepotentielderestaurerlessolsmarginaux,toutencontribuantàaméliorerla
sécurité énergétique et à atténuer les changements climatiques. Dans la présente
étude,lessystèmesdeculturedeJ.curcasexistantsauBurkinaFasoontétéidentifiés
et étudiés quant aux dynamiques de la biomasse et du carbone (C) dans les sols.
Combinéesàdesinformationssurlatransformationdesgraines,cesdonnéesontété
intégréesdansuneanalyseducycledevie(ACV)pourcalculerlesémissionsdegazà
effetdeserre(GES)etlepotentield'économied'énergiedelachainedeproductionde
biocarburantsdanssonensemble.
CinqsystèmesdeculturedeJ.curcasontétéidentifiés:l’associationavecdes
culturesannuelles,lesplantationsavecunegestionintensive,lereboisementdesols
marginaux,leshaiesvivestraditionnellesetleshaieslelongdescodonspierreux.Des
mesures directes de la biomasse aérienne et souterraine ont permis d’identifier les
différentesphasesdecroissanceetdedévelopperdeséquationsallométriquesreliant
la biomasse aérienne et souterraine au diamètre du tronc (R²>0.9). En outre, des
modèlesdecroissanceempiriquesontétédéveloppéspourchaquesystème,prédisant
laproductiondebiomasseaérienneenfonctiondel’âge.Lesrésultatsdecesmodèles
montrentquelaproductiondebiomasseestmaximaleentrela10èmeetla15èmeannée
aprèslaplantation.Lesplusgrosstocksdebiomasse,jusqu’à21thaͲ1, sontobservés
dans les systèmes en association avec des cultures annuelles et dans les plantations
intensives alors que le système de reboisement des sols marginaux présente la
productiondebiomasselaplusfaible(0.1thaͲ1).Acausedutauxdemortalitéélevé
desjeunesplants,cesystèmen’apaspuêtremodélisé.
LesanalysesdesolcomparantlessolssousJ.curcasdepuisquatreansavec
lessolssousculturesannuellesn’ontpasmontrédedynamiqueévidenteduCdansle
sol.Unechronoséquencede20anspourunehaieviveacependantpermisdemettre
enévidenceuneaugmentationsignificativeduCdanslespremiers20cmdusol.
PourtouteslesfilièresdeproductiondeJ.curcas,l’analysedecycledeviea
montrédesréductionsdeGESjusqu’à82%etunetrèshauteefficacitéénergétiquepar
rapportauxcarburantsfossiles.Laproductionlocaled’huilevégétaleetsonutilisation

dans les moteurs stationnaires affiche la meilleure performance. Néanmoins, les
plantationsdeJ.curcasmontrentuneefficacitétrèsfaibleentermesd'utilisationdes
terres(6.5Ͳ9.5GJhaͲ1),augmentantainsilepotentielpourunchangementd’utilisation
dusol.BienquelesstocksdeCaugmententlorsdel’intégrationduJ.curcasdansles
terresencultures,ledéplacementd’activitésagricolespourraitindirectementrésulter


àunchangementd’utilisationdusoletainsiàunediminutionduC.L’énergiehumaine
représentait 24% du bilan énergétique global, indiquant un besoin de main d'œuvre
trèsélevédanslessystèmesdeJ.curcasàpetiteéchelle.L'évaluationmonétairedes
crédits carbone pour le marché international ne promettait pas de recettes
significatives.
Globalement,ilapuêtredémontréquelaproductiondebiocarburantdeJ.
curcas pouvait contribuer à l’atténuation des changements climatiques et à
l’indépendance énergétique. Cependant, l’inefficacité de l'utilisation de terres, le
besoin de main d'œuvre très élevé et l’inaptitude des terres marginales pour la
productiondeJ.curcasmettentcetteplanteenconcurrencedirecteaveclescultures
alimentaires et la rendent donc non viable pour les petits agriculteurs. Tant que la
culturedeJ.curcasn’estpasintensifiéegrâceàdesaméliorationsvariétalesetàune
gestion agricole optimisée, les haies vives sont préférables: elles offrent divers
bénéfices aux agriculteurs et contribuent à l’approvisionnement énergétique des
régionsrurales.


ÖkobilanzierungderKohlenstoffͲundEnergiebilanzenvonJatropha
ProduktionssystemeninBurkinaFaso


KURZFASSUNG



Moderne Bioenergie stellt für Burkina Faso eine attraktive Alternative zu
Erdölimporten und traditioneller Biomassenutzung dar. In diesem Kontext wurde
JatrophacurcasbekanntalseinesehranspruchsloseEnergiepflanze,dessenAnbauzur
RekultivierungvonmarginalenStandorten,zurnationalenEnergieversorgungundzum
Klimaschutz beitragen kann. Im Rahmen der vorliegenden Forschungsarbeit wurden
existierendeJ.curcasSystemeinBurkinaFasoidentifiziertundaufihreBiomasseͲund
BodenkohlenstoffͲDynamik untersucht. Zusammen mit Informationen zur
Weiterverarbeitung der Samen wurden alle Daten in einem Life Cycle Assessment
(LCA) zur Berechnung der Treibhausgasemissionen und des EnergieeinsparungsͲ
potenzialsderJ.curcasBioenergieͲProduktionssystemezusammengeführt.
Insgesamt konnten fünf J. curcas Systeme identifiziert werden: Mischanbau
mit einjährigen Kulturen, intensiv bewirtschaftete Plantagen, Aufforstung von
marginalen Flächen, traditionelle Lebendhecken und Hecken entlang von
Kontursteinmauern. Durch direkte Messungen von oberͲund unterirdischer Biomasse
der J. curcas Bäume konnten unterschiedliche Wachstumsphasen definiert und
allometrische Modelle zur indirekten Biomassebestimmung entwickelt werden. Es
zeigtesicheinesehrstarke(R²>0.9)allometrischeBeziehungzwischensowohlHolzͲals
auch Wurzelmasse und Stammdurchmesser. Des Weiteren konnten empirische
Wachstumsmodelle zur Vorhersage der Holzbiomasse in Abhängigkeit des Alters
erstellt werden. Entsprechend der Modelle erreicht die Biomasseproduktion ihren
Höhepunkt zwischen dem zehnten und fünfzehnten Wachstumsjahr. Jatropha curcas
im Mischanbau und in intensiv bewirtschafteten Plantagen erreichte die höchsten
Biomassewerte (21 t haͲ1), während das Aufforstungssystem mit einer Biomasse von
wenigerals0.1thaͲ1diegeringstenWerteaufwies.AufgrundderhohenMortalitätder
jungen Bäume auf den marginalen Standorten konnte das Biomassewachstum dieses
Systemsnichtmodelliertwerden.VergleichendeBodenanalysenvonvierJahrealtenJ.
curcas Standorten mit Flächen unter einjährigen Kulturen ergaben keine eindeutige
TendenzvonVeränderungendesBodenkohlenstoffs.NurineinerChronosequenzvon
Böden unter Lebendhecken über 20 Jahre konnte ein signifikanter Anstieg des

Kohlenstoffsindenersten20cmdesBodensfestgestelltwerden.
Für alle Produktionswege der J. curcas Bioenergie konnten eine bis zu 82%
hohe Verringerung der Treibhausgasemissionen und bis zu 85% Energieeinsparungen
im Vergleich zu fossilen Brennstoffen festgestellt werden. Die dezentrale Produktion
vonPflanzenölunddessenVerbrauchinstationärenDieselmotorenzeigtediebesten
Ergebnisse. Eine sehr geringe Landnutzungseffizienz (6.5Ͳ9.5 GJ haͲ1) der J. curcas
Plantagensysteme erhöhen jedoch den Druck auf andere Landnutzungsformen. Auch
wenn die Integration von J. curcas in landwirtschaftliche Systeme zu einer größeren
Kohlenstoffspeicherung führt, kann die Verdrängung der Nahrungsmittel von den


Flächen zu indirekten Landnutzungsänderungen und dortigen Kohlenstoffverlusten
führen. Zusätzlich bedarf die Kultivierung von J. curcas in kleinbäuerlichen Systemen
einen sehr hohen körperlichen Arbeitsaufwand, der 24% der gesamten Energiebilanz
konstituiert. Eine monetäre Bewertung der Kohlenstoffeinsparungen durch dessen
HandelaufinternationalenMärktenversprachnurgeringfügigeErträge.
Zusammenfassend kann gesagt werden, dass J. curcas Systeme in Burkina
FasosowohlzumKlimaschutzalsauchzurEnergiesicherungbeitragenkönnen.Durch
die sehr geringe Landnutzungseffizienz, den hohen Arbeitsaufwand und die fehlende
Ertragsleistung auf marginalen Standorten wird J. curcas jedoch zu einer direkten
Konkurrenz zu Nahrungsmitteln und stellt keine praktikable Option für Kleinbauern
dar. Solange der Anbau von J. curcas durch verbessertes Pflanzmaterial und
optimiertes Management nicht intensiviert werden kann, sollte der Anbau von J.
curcasinHeckensystemenvorgezogenwerden.DiesebietenvielfältigeVorteilefürdie
Bauern während die Samenproduktion zur Energieversorgung in ländlichen Gebieten
beitragenkann.



TheDissertation’sFootprint



Dealingwithcarbon,bioenergy,andecologicalsustainabilityoverfouryears,Ifeltthe
needtoknowthecarbonfootprintofmydissertation.Isummedupthemilesspentin
airplanesflyingbackandforthtoBurkinaFaso,thehoursinapickͲupdrivingthrough
theAfricanbush,andalltheJatrophatreesIcut.
I came up with a total 14 t CO2 emitted to the atmosphere through my
dissertation1.Asyouwillunderstandafterreadingthedissertation,approx.200mof
JatrophalivingfenceorhalfahectareJatrophaplantationwouldbeneededtooffset
thisamountofcarbon.Currently,Iamnotinthepositiontoundertaketheplantings
and maintenance, therefore I decided to buy my way out. I donated € 322 from the
Dreyer research budget to atmosfair gGmbH who is investing money in energizing
projectsworldwide.NowIcansaythatthepreparationofmydissertationwasalmost
carbonneutral!
However, the achievements resulting from my dissertation shouldn’t be
neutral but hopefully contribute to a sound policy of Jatropha biofuel production
fulfillingmostofthepromisesassociatedwithJatropha.


Enjoyreadingthisdissertation!

SophiaEmiliaBaumert




1

 Notincludedaredailyfoodintakeforbrainactivity,dailypublictransportationtoZEF,electricityand
heatingexpensesintheoffice,paperpaperpaper,andthousandsofmouseclicksbrowsingthrough

theinternet.


TABLEOFCONTENTS
1

INTRODUCTION.................................................................................................1

1.1

Problemsetting.................................................................................................1

1.2

JatrophacurcasanditsrelevanceforBurkinaFaso..........................................2

1.3

Researchneeds..................................................................................................4

1.4

Researchobjectives...........................................................................................6

1.5

Outlineofthethesis..........................................................................................6

2

STUDYREGION...................................................................................................8

2.1

Climateandvegetation.....................................................................................8

2.2

Soilsandlanduse............................................................................................11

2.3

Agriculture.......................................................................................................11

2.4

Energyusepattern..........................................................................................12

3

JATROPHAINBURKINAFASO..........................................................................14

3.1

Introduction.....................................................................................................14

3.2
3.2.1
3.2.2
3.2.3

3.2.4

Materialsandmethods...................................................................................16
Samplingdesignanddatacollection...............................................................16
Geographicdistributionofthestudysites......................................................19
ShadingeffectofJatrophacurcasplantings...................................................21
Statisticalanalyses...........................................................................................22

3.3
3.3.1
3.3.2
3.3.3

Results.............................................................................................................23
StakeholdersinJatrophacurcasactivities......................................................23
Systemclassificationandcharacterization.....................................................27
LandallocationtoJatrophacurcascultivation................................................35

3.1
3.1.1
3.1.2

Discussion........................................................................................................37
ManagementpracticesinJatrophacurcassystems.......................................37
Thelandusedilemma.....................................................................................40

3.2

Conclusionsandrecommendations................................................................42

4

DYNAMICSINABOVEͲANDBELOWͲGROUNDBIOMASS................................44

4.1

Introduction.....................................................................................................44

4.2
4.2.1
4.2.2
4.2.3

Materialsandmethods...................................................................................46
Sampledesignandcontrolforconfounders...................................................46
Studysites........................................................................................................47
Measurementsoftreedimensionsanddrymatterproduction.....................49


4.2.4
4.2.5
4.2.6
4.2.7

Fruityieldobservations...................................................................................51
Statisticalanalyses...........................................................................................51
Modelvalidation..............................................................................................55
Carbonstockestimation..................................................................................56

4.3

4.3.1
4.3.2
4.3.3
4.3.4
4.3.5
4.3.6
4.3.7

Results.............................................................................................................56
MorphologicalandphysiologicalattributesofJatrophacurcastrees............56
Fruitcharacteristicsandseedyield.................................................................58
Growthstages..................................................................................................59
Allometricrelationships..................................................................................60
Empiricalgrowthmodels.................................................................................66
CarbonstorageinJatrophacurcassystems....................................................70
Modelvalidation..............................................................................................71

4.4
4.4.1
4.4.2
4.4.3
4.4.4

Discussion........................................................................................................72
SeedproductivityofJatrophacurcastrees.....................................................72
AllometryofJatrophacurcas..........................................................................73
Biomassgrowthmodeling...............................................................................76
CarbonsequestrationpotentialinJatrophacurcassystems..........................77

4.5

Conclusionsandrecommendations................................................................78

5

DYNAMICSOFSOILORGANICCARBON...........................................................80

5.1

Introduction.....................................................................................................80

5.2
5.2.1
5.2.2
5.2.3
5.2.4
5.2.5
5.2.6
5.2.7

Materialsandmethods...................................................................................82
Soilsampling....................................................................................................82
Chronosequencestudy....................................................................................83
13
Cnaturalabundancetechnique....................................................................84
Leaffallandleafdecomposition.....................................................................84
Soilanalyses.....................................................................................................85
Soilcarbonbudget...........................................................................................87
Statisticalanalyses...........................................................................................87

5.3
5.3.1
5.3.2
5.3.3
5.3.4
5.3.5
5.3.6

Results.............................................................................................................88
Soilproperties..................................................................................................88
Soilorganiccarbondynamics..........................................................................91
Soilorganiccarbonchangeoversoilchronosequence...................................95
Changesinɷ13Cvalues....................................................................................96
Leaflitterfallanddecompositionrates...........................................................97
Contributionoforganicmaterialtothesoilcarboncycle............................100

5.4
5.4.1
5.4.2
5.4.3
5.4.4
5.4.5

Discussion......................................................................................................101
Soilcarbondynamicsincontourhedges.......................................................101
Soilcarbondynamicsinlivingfences............................................................102
Soilcarbondynamicsinplantationsystems.................................................103
Soilcarbondynamicsinafforestationsystems.............................................104
Carboninputandturnover............................................................................104

5.4.6
5.4.7

Globaltargetsandlocalneeds......................................................................105
Remarksonthemethodology.......................................................................106

5.5

Conclusionsandrecommendations..............................................................107

6

GREENHOUSEGASANDENERGYSAVINGSINJATROPHACURCASBIOFUEL
PRODUCTIONSYSTEMS.................................................................................108

6.1

Introduction...................................................................................................108

6.2
6.2.1
6.2.2
6.2.3
6.2.4
6.2.5
6.2.6

Methodology:Lifecycleassessment.............................................................110
Goalandscopedefinition..............................................................................110

Inventoryanalysis..........................................................................................114
Jatrophacurcascultivation...........................................................................116
BiomasscarbonstocksandlandͲusechange................................................118
TransformationphaseofJatrophacurcasseeds...........................................120
Jatrophacurcasoilconsumptionandenergysubstitution...........................122

6.3
6.3.1
6.3.2
6.3.3
6.3.4
6.3.5

Results...........................................................................................................123
Cultivationphase...........................................................................................123
LandͲusechangeandcarbonbalance...........................................................126
Fromwelltotank...........................................................................................127
Energyconsumption......................................................................................130
Carbonoffsets...............................................................................................133

6.4
6.4.1
6.4.2
6.4.3
6.4.4
6.4.5

Discussion......................................................................................................133
Managementascarbonemittingfactor.......................................................133
LandͲuseeffects.............................................................................................135

PerformanceofJatrophacurcasbiofuelproductionpathways....................137
EnduseofJatrophacurcasfuels...................................................................138
PotentialofglobalcarbontradingforproͲpoormitigation..........................139

6.5

Conclusionsandrecommendations..............................................................140

7

GENERALOVERVIEWANDOUTLOOK............................................................142

7.1
7.1.1
7.1.2

JatrophacurcasinBurkinaFaso....................................................................142
Carbonandenergybalances.........................................................................145
Potentialofcarbontrading...........................................................................146

7.2
7.2.1
7.2.2

Methodologicalissues...................................................................................147
Estimationofbiomasscarbon.......................................................................147
Changesinsoilcarbon...................................................................................149

7.3

Overallconclusions........................................................................................149

8

REFERENCES...................................................................................................151

9

APPENDICES...................................................................................................165

ACKNOWLEDGEMENTS


LISTOFACRONYMSANDABBREVIATIONS

AEZ
AGB
BGB
C
CDM
CED
CH4
CI
CO2
D
FGD
GHG
GJ
GWP
H

iLUC
JME
K
Kgoe
LCA
LHV
LUC
MJ
N
NER
NGO
N2O
OM
P
PD
RED
RD
RHI
RMSE
RSR
SE
SOC
SVO
SWC
TOC














































AgroͲecologicalzone
AboveͲgroundbiomass
BelowͲgroundbiomass
Carbon
Cleandevelopmentmechanism
Cumulativetotalenergydemand
Methane
Confidenceinterval
Carbondioxide
Diameteratstembase
Focusgroupdiscussion
Greenhousegas
GigaJoule
Globalwarmingpotentials
Height
IndirectlandͲusechange
Jatrophamethylester
Potassium
Kilogram(s)ofoilequivalent
Lifecycleassessment
Lowerheatingvalue

LandͲusechange
MegaJoule
Nitrogen
Netenergyratio
NonͲgovernmentalorganization
Nitrousoxide
Organicmaterial
Phosphorus
Plantdensity
Renewableenergydirective
Relativedifference
Relativeheightincrement
Rootmeansquarederror
RootͲshootratio
Standarderror
Soilorganiccarbon
Straightvegetableoil
Soilandwaterconservation
Totalorganiccarbon


Introduction

1

INTRODUCTION

1.1

Problemsetting

SubͲSaharanAfricaishometotheworld’spoorestpopulationwith90%livinginrural
areas and depending on subsistence agriculture for their livelihoods (Bationo and
Buerkert2001).Thehighlevelsofpovertyare,amongstothers,reflectedintheenergy
consumptionpattern,withaverylowshareofmodernenergyandahighrelianceon
traditional biomass energy (Karekezi 2002) accounting for more than 80% of the
primary energy supply (IEA 2006). With an annual population growth rate of 2.5%
(World Bank 2012) the need for energy is constantly increasing, leading to highly
unsustainable biomass consumption (Bugaje 2006; Tatsidjodoung et al. 2012). Trees,
an essential element for the stability of ecosystems, are removed without providing
theopportunityforreͲgrowth(RutzandJanssen2012),andtheenergeticuseofcrop
residueslimitsthereͲcyclingofsoilnutrients,whichleadstodecliningsoilfertility(Lal
2006).ParticularlyinthelowͲinputagriculturalsystemswhereproductivityͲenhancing
technologiesarelargelyoutofreach,soilqualityiskeytoagriculturalproduction(Vlek
2005). Declining soil fertility and land degradation are among the major humanͲ
induced problems currently facing agricultural production throughout SubͲSaharan
Africa(KatyalandVlek2000,Zida2011).
Growing public awareness of the energy dilemma prevailing in SubͲSaharan
Africahasdirectedinternationalattentionontheuseofmodernbioenergy2(Ndonget
al.2009).ParticularlyinAfrica,whereoneͲthirdofthetotallandispotentiallyavailable
forbiofuelproduction(Caietal.2010)andalargeshareofthepopulationisinvolved
inagriculture,biofuelproductioncanoffermanybenefitstotheruralpoor(Blinetal.
2013).BiofuelscouldprovideresourceͲpoorcountrieswithameanstoinvestintheir
ownruralareasinsteadofexportingtheircapitaltopurchasefossilfuel.Moreover,the
positivecorrelationbetweeneconomicdevelopmentandaccesstoenergyresourcesis
long recognized (Karekezi 2002; Bugaje 2006). Internationally, energy crops can
contributetoclimatechangemitigationthroughcarbonsequestrationinbiomassand

2

 Modern bioenergy is defined as bioenergy relying on sustainably used biomass as opposed to
traditionalbiomassusedepletingnaturalresources(GoldembergandCoelho2004).

1


Introduction

soil and through substitution for fossil fuels or unsustainably harvested fuel wood
(Bass et al. 2000). The carbon offsets can then be monetarily valuated via carbon
trading mechanisms (e.g., Clean Development Mechanism (CDM), Voluntary Carbon
Markets),whichisoftencitedasanadditionalincomeopportunityforAfricanfarmers
(Bryanetal.2008).However,alsoinSubͲSaharanAfrica,therearerisksassociatedwith
bioenergy production such as negative impacts on ecosystems (Ndong et al. 2009),
competitionwithfoodproduction,andincreasedfoodprices(vonBraun2008).
In this context, the tree species Jatropha curcas has become popular as an
energycropbasedonearlyclaimsofhighproductivityunderlowwater,nutrientand
managementrequirements.Accordingtotheclaims,thecropcanthriveonmarginal
landinsemiͲaridregions,contributestolandreclamationanddoesnotcompetewith
foodcropsforscarceresources(e.g.,Heller1996;Francisetal.2005;Jongschaapetal.
2007;Henning2009;Achtenetal.2010b;Contranetal.2013).

1.2

JatrophacurcasanditsrelevanceforBurkinaFaso

Jatropha curcas Linnaeus has its origin in Central America and Mexico and was
probablyimportedbythePortugueseseafarerstotheCapeVerdeIslandsandGuinea
Bissau in the 16th century and then distributed over wider parts of Africa and Asia
(Heller1996;DomergueandPirot2008;Henning2009).Jatrophacurcasbelongingto

thegenusEuphorbiaceaeisasmalltreethatproducesfruitscontainingseedswithan
oilfractionof30to35%(Jongschaapetal.2007;Achtenetal.2008).Theoilistoxic
and not edible for humans and animals, but it has a very good burning quality
(Jongschaapetal.2007;Blinetal.2013).Thetreeishighlyadaptabletoavarietyof
growing conditions (the J. curcas belt is roughly situated between 30°N and 35°S
(Jongschaapetal.2007))andisexpectedtoyieldover50yearswithagestationperiod
of3to4years(Jongschaapetal.2007;vanEijcketal.2010).Traditionally,J.curcasis
planted as living fences protecting fields from animals and contributing to erosion
control. The oil is originally used for the production of soap and for medicinal
purposes. With the rising interest in biofuel, the use of the oily seeds as an energy
feedstock has internationally come into focus. The oil can be mechanically extracted

2


Introduction

with a simple technology and used directly as straight vegetable oil (SVO) in diesel
engines(Blinetal.2013)suchasinnationalpowerstationsandcanreplaceimported
fossilfuel(NonyarmaandLaude2010;Tatsidjodoungetal.2012).Moreover,theuse
of SVO offers the possibility of decentralized production and consumption (e.g., for
agricultural activities, power generation, rural industry, and cooking) avoiding long
transportationdistancesandcomplicatedtransformationprocessesasisthecasewith
biodiesel (FACT Foundation 2009; Blin et al. 2013). These decentralized schemes are
particularlypopularinWestAfricancountrieswithsevereenergypovertyinruralareas
(Blinetal.2013).
Owing to its great potential, J. curcas became idealized as a solution for
energyͲpoor countries, and triggered largeͲscale investments (Achten et al. 2010b)
with cultivation hotspots in India, Zambia, Madagascar, Tanzania, Brazil, Mexico and
Ghana (Gao et al. 2011). However, most J. curcas projects were not scientifically

grounded, but rather driven by overͲoptimistic claims leading to manifold project
failures(vanEijcketal.2010).Bynow,manylessonshavebeenlearntshowingthatthe
full potential of this tree species is not easily exploitable and particularly not
simultaneously applicable (Coltran et al. 2013). Jatropha curcas is still an
undomesticatedplantwithagreatvariabilityinproductivity(e.g.,Achtenetal.2010c;
Liyama et al. 2012; Contran et al. 2013). Under the current knowledge status, a
definition of siteͲspecific agronomic management regimes for optimal production
levels is impossible (Singh et al. 2013) leading to subͲoptimal management practices
andlowyields(Liyamaetal.2012,Singhetal.2013).Moreover,ithasbeenrealized
that trees grown on marginal soils with marginal inputs will produce marginal yields
(Lal 2006; Elbehri et al. 2013), thus trading off marginal land restoration and biofuel
production.RecentstudiesfoundoutthatJ.curcascansurviveinaridconditionsdue
to its droughtͲavoidance strategy (Krishnamurthy et al. 2012; Rao et al. 2012).
However,thehighestproductivitylevelsarereachedunderhumidclimates(Maeset
al.2009).Consequently,economicallydrivenJ.curcascultivationtakesplaceinregions
with good soils and good rainfall conditions where it thus competes with food
production(Tatsidjodoungetal.2012).Finally,thecontributionofJ.curcascultivation

3


Introduction

toruraldevelopmentandruralenergyaccessisnotselfͲevident,andstronglydepends
ontheappliedproductionsystemanditsintegrationoftheruralpopulation(Franciset
al.2005;Wanietal.2006,Achtenetal.2010b;Dyeretal.2012).
Since 2007, J. curcas has been one of the most strongly promoted biofuel
cropsinBurkinaFaso(Tatsidjodoungetal.2012).Studiesassessingthelandavailability
for biofuel production in semiͲarid regions excluding agricultural land and land with
high biodiversity (Cai et al. 2011; Wicke et al. 2011; Dauber et al. 2012) showed

substantiallandavailabilityinBurkinaFaso(Wickeetal.2011).ThecontributionofJ.
curcas cultivation to the national energy supply and to the amelioration of the soil
resources could thus be significant. Understanding the potential and challenges of J.
curcas, the Burkinabe government began to design a national biofuel policy in 2009,
prioritizing food security, environmental and biodiversity protection, and inclusion of
smallͲscale farmers in biofuel activities (MMCE 2009; Nonyarma and Laude 2010;
Tatsidjodoungetal.2012).InordertoavoidenvironmentallyfatallandͲusechangeand
competition between food and energy, J. curcas should be preferably grown in
combination with annual crops or on soils low in productivity (MMCE 2009). The
allocationoflandtolargeͲscaleplantationswasregardedwithcaution(MMCE2009).

1.3

Researchneeds

Overall, the productive capacity of J. curcas has been rarely studied in Burkina Faso
(Sop et al. 2012), and the effects of different production models on people and
environment have not yet been evaluated (Tatsidjodoung et al. 2012). It is generally
agreed that sustainable bioenergy systems must provide net energy gains, have
environmental and local socioͲeconomic benefits, and produce bioenenergy in large
quantities without impacting food supplies (Fritsche et al. 2005; Hill et al. 2006;
Mangoyana2008,Elbehrietal.2013).Further,theassociationofJ.curcaswithcarbonͲ
neutral biofuel and climate change mitigation remains to be justified for the
production systems inBurkina Faso in view of agroͲinputs in energy crop production
and impacts bound to landͲcover change from ecosystems high in carbon stock to
energycrops(Fargioneetal.2008).CarbonͲoffsetcalculationsalsoprovideevidenceof

4

Introduction

therelevanceofinternationalcarbontradingforBurkinaFaso.
Life cycle assessment (LCA) is a common tool to evaluate environmental
sustainability of biofuel production systems in terms of energy efficiency and carbon
neutrality(Gnansounouetal.2009).Todate,noLCAhasbeenconductedforJ.curcas
biofuel production in Burkina Faso, and J. curcas initiatives are proceeding without
knowledge of caseͲspecific environmental consequences. Ndong et al. (2009)
presented a study for West Africa, but they did not include carbon stock changes in
biomassandsoilresultingfromlandconversion,andassumedmorethan50%higher
seed yields than actually observed in Burkina Faso. OverͲoptimistic J. curcas yield
estimationswerenamedbyGasparatosetal.(2012)asamajorerrorsourceinLCAs.
Achtenetal.(2012)criticizedtheabsenceofcarbonstockchangesinbiomassandsoil
inmostLCAcalculations,althoughbioenergyͲinducedlandͲuseandlandͲcoverchanges
areknowntohavehighimpactsonenvironmentalsustainability(Fritscheetal.2005).
ForJ.curcassystems,thismeansthatabetterestimationofcarbonstocksisneededas
already called for by Reinhardt et al. (2007). Moreover, investigations of the soil
carbon dynamics under J. curcas systems are important for the assessment of their
claimedlandrehabilitationpotential.
LongͲterm observations of temporal biomass dynamics in J. curcas systems
are out of reach, as most J. curcas systems are in their infancy. However, the
developmentofempiricalgrowthmodelsbyfittingchronosequencesoftreesdiffering
inagecouldprovidebiomasspredictionsovertimewithinaveryshortperiodoftime
(Walker et al. 2010). The establishment of allometric relationships between biomass
and stem diameter in J. curcas could further facilitate nonͲdestructive tree biomass
estimation.Thechronosequenceapproachisalsowidelyappliedforthedetectionof
dynamics in soil organic carbon (Walkeret al. 2010). Some studies have investigated
allometric relationships and biomass dynamics in J. curcas (Ghezehei et al. 2009;
Achtenetal.2010a;Beheraetal.2010;Rajaonaetal.2011;Hellingsetal.2012),albeit
basedonamodestsamplesize.NosuchresearchhasbeenconductedinWestAfrica,

and only few studies investigated changes in soil after afforestation with J. curcas
(Ogunwoleetal.2008;Soulama2008).

5


Introduction

1.4

Researchobjectives

ConsideringthelackofscientificknowledgeandtheexpandingcultivationofJ.curcas,
the aim of this dissertation is to assess the environmental sustainability of J. curcas
biofuelproductionsystemsinBurkinaFaso.Tothisend,thecarbonͲandenergyͲsaving
potential of existing J. curcas production systems is analyzed under consideration of
carbon sequestration in biomass and soil. The findings are expected to support
decisionmakingforenvironmentallysoundJ.curcasproductionthatcancontributeto
energy security, climate change mitigation and rural development, also beyond
BurkinaFaso’sborders.
Accordingly,themainresearchobjectiveswereto:
(i)CharacterizeandclassifyJ.curcascultivationsystemsprevailinginBurkinaFaso;
(ii) Analyze the potential for carbon sequestration in aboveͲ and belowͲground
biomassstocksviaallometricequationsandempiricalgrowthmodels;
(iii)AssessthesoilcarbondynamicsafterafforestationwithJ.curcas;
(iv)Conductalifecycleassessmentforthecalculationoftheoverallcarbonandenergy
budgetofJ.curcasproductionpathways.

1.5

Outlineofthethesis

The thesis comprises seven chapters. The general introduction gives an overview of
theenergysituationinBurkinaFasoandtheroleJ.curcasplaysinthiscontext.Chapter
2describesthestudyregion.InChapter3,theresultsofanextensiveinventorystudy
identifyingtheprevailingJ.curcasmanagementsystemsinBurkinaFasoarepresented.
Through interviews with stakeholders involved in the J. curcas production chain,
classificationcriteriaforfivemanagementsystemsaredeveloped.Thefindingsofthe
inventory serve as basis for all further investigations. Chapter 4 presents the
quantification of the carbon sequestration potential in standing biomass of the
identified J. curcas systems. Allometric equations for nonͲdestructive biomass stock
estimationsandempiricalgrowthmodelsdemonstratingbiomassgrowthofJ.curcas
stands over the years are developed and tested. The aspect of soil carbon
sequestration under J. curcas systems is elaborated in Chapter 5. Data from a soil

6


Introduction

survey concentrating on soil organic carbon stocks and their changesunder J. curcas
systems relative to reference sites are presented. Chapter 6 integrates the results of
Chapter 3, 4 and 5 in a life cycle assessment and presents different J. curcas
productionͲtransformationͲconsumption pathways in regard to their potential for
carbonemissionreductionandenergysavings.Finally,inChapter7themainfindings
ofthestudyaresummarizedanddiscussed,andrecommendationsforexploitationof
thepotentialofJ.curcasandsuggestionsforfurtherresearchareformulated.

7

Studyregion

2

STUDYREGION

Burkina Faso ("country of the honorable people") is a landlocked country situated in
the heart of West Africa. It covers an area of 274,000 km² located between 09°20’ Ͳ
15°03’ N and 05°03 W Ͳ 02°20’ E and bordered by Niger, Mali, Ghana, CôteͲd’Ivoire,
Benin and Togo (CIA 2012). The country is divided into 13 regions and 45 provinces
withOuagadougouasthecapitalcity.Thepopulationcounts17.813millionpeople(65
people kmͲ²) with a population growth rate of3% (CIA 2012). More than 80% of the
population resides in rural areas and is engaged in smallͲscale lowͲinput agriculture
(CIA 2012). Burkina Faso’s economy heavily relies on cotton and gold exports for
revenues, as it has only few natural resources and a weak industrial sector. Overall,
high population density, lack of natural resources, poor industrial development and
low agricultural productivity are the main reasons behind the persisting poverty in
Burkina Faso where 46% of the population live below the poverty line (World Bank
2013b).

2.1

Climateandvegetation

BurkinaFasoisdividedintothreeagroͲecologicalzones(AEZ),i.e.,theSudanianinthe
south(9°3’Ͳ11°3’N),theSudanoͲSahelianinthecentralregion(11°3’Ͳ13°3’N)andthe
Sahelian in the north (13°5’Ͳ15°5’N). It has a tropical climate with two alternating
seasons: a long dry spell from November to May with the continental trade wind
(Harmattan) coming from northeast and a short rainy season from June to October

with moist air coming from oceanic high pressure (Figure 2.1) (Thiombiano and
Kampmann2010).
Located in the transition zone between the Sahara Desert to the north and
coastalrainforeststothesouth,BurkinaFasoispronetoextremeweathereventssuch
asrecurrentdroughts,floodsandwindstorms(WorldBank2013a).InterͲannualand
interͲdecadalclimatevariabilitywilllikelyincrease;howeverahighlevelofuncertainty
isassociatedwithclimatechangeprojectionsforWestAfrica(IPCC2001;WorldBank
2013a).

8


Studyregion

BoboͲDioulasso(Sudanianzone)

40

300

30

200

20

100

10

0

Temperature(°C)

Precipitation(mm)

400

0
1

2

3

4

5

6

7

8

9

10 11 12





Precipitation(mm)

200

40
30

150
20
100
10

50
0

Temperature(°C)

Ouagadougou(SudanoͲSahelianzone)

250

0
1

2

3

4

5

6

7

8

9

10 11 12




Kongoussi(Sahelianzone)

35
30

200

25
150

20

100

15
10

50

5

0

Temperature(°C)

Precipitation(mm)

250

Prec
PET
Temp

0
1

2

3

4

5

6

7

8

9

10 11 12

Months


Figure2.1

LongͲterm (1961Ͳ1990) average monthly temperature, rainfall and
evapotranspiration(PETmm)(FAO2013)





9




Studyregion

Table2.1

ClimaticconditionsintheagroͲecologicalzones(AEZ)inBurkinaFaso

AEZ

Climatic
zone

Sudanian
SudanoͲ
Sahelian

LGP
(days)

Precipitation
(mm)

%of
national
territory

No. of dry
months

subͲhumid 180Ͳ269

900Ͳ1200

32.4

5Ͳ6

semiͲarid

700Ͳ900

38.9

6Ͳ7

90Ͳ179

Sahelian
aridzone 90
<700
28.7
>7
Source:AdaptedfromKagone2001andFontèsandGuinko,1995.LGP:length
ofgrowingperiod.

In the Sahelian zone the natural vegetation is composed of grassy and
shrubby steppes in the north and shrubby savanna in the south (INSD, 2002;
ThiombianoandKampmann2010).TreespeciessuchasFeidherbiaalbida,Sclerocarya
birrea, Tamarindus indica, Balanites aegyptiaca, Ziziphus mauritiana, Lannea
microcarpa,andAzadichtaindicaarethe mostcommonintheagroforestryparkland
systems.IntheSudanoͲSahelianAEZ(NorthSudan)annualrainfallrangesfrom700to
900mmfromnorthtosouth.Vegetationchangesfromgrassyandshrubbysteppesin

the north to shrubby and woody savannas in the southern parts with parkland tree
speciessuchasVittelariaparadoxa,Feidherbiaalbida,Adansoniadigitata,Tamarindus
indica, Lannea microcarpa, Azadichta indica,and Bombax costatum (Thiombiano and
Kampmann 2010). The Sudanien zone (South Sudan) is characterized by mosaics of
cropland, fallow areas in various stages of regeneration, and typical agroforestry
parklandwiththemaintreespeciesFaidherbiaalbidia,Vittelariaparadoxa,andParkia
biglobosa (Boffa 1999; Thiombiano and Kampmann 2010). Pressure on the natural
vegetation is particularly high due to expanding cultivation of cotton, and high
migration from the northern parts of Burkina Faso (Gray 1999) coupled with
unsustainable firewood collection, annual bushfires, intensive pasturing and
settlements(CommuneRuraledeBoni2009).Charcoalexploitationnotonlyforlocal
consumption but also for supplies to Ouagadougou is additionally triggering
deforestation(1.45%annually)(Ouedraogo2007;Ouedraogoetal.2010).

10


Studyregion

2.2

Soilsandlanduse

MostofBurkinaFasoiscoveredbyferriclixisols(WRB1998)(leachedferruginoussoils
(CPCS 1967)) and leptosols or lithisols (poorly evolved soils of erosion). Cambisols,
vertisols, glysols and ferralsols are of limited extent, and are found localized
throughout the country (Thiombiano and Kampmann 2010). Generally, the soils are
inherentlylowinsoilfertility(organiccarbon<1%),havelowwaterholdingcapacity,
andatendencytodevelopsoilsurfacecrusting(Zougmoré2003).Bushfiresforland
clearing make the soils susceptible to wind erosion during the dry season, and high

rainfall intensities trigger water erosion at the onset of the rainy season (Zougmoré
2003).AccordingtoFAO(2009),44%ofthetotallandareainBurkinaFasoisalready
affectedbyseverelanddegradation.
ThelandresourcesinBurkinaFasoaredividedasfollows(WorldBank2008):
45% agricultural land (12 Mio ha) with 50% under cultivation (6.3 Mio ha) and 50%
underpermanentcropsandpastures(includingabandonedcroplandandlandnotyet
cultivated),24%forestarea,and10%undersettlement(other:21%).Highpopulation
growthand acceleratinglanddegradationarekeydriversbehindcroplandexpansion
withanannualrateof0.2%(0.96%insouthernBurkinaFaso)attheexpenseofgrazing
area,forestsandwoodland(FAO2001inOuedraogoetal.2010).

2.3

Agriculture

The agricultural sector dominated by small family farms on rainfed land and
characterized by low labor and input productivity (Breman et al. 2001 in Zougmoré
2003) provides income to more than 80% of the population (MED 2003). Millet
(Pennisetumglaucum),redandwhitesorghum(Sorghumbicolour),maize(Zeamays),
andcowpeas(Vignaunguiculata)arethemainsubsistencecropsandcover80%ofthe
cultivated area. Cotton (Gossypium herbarceum), groundnuts (Arachis hypogaea L.),
and sesame (Sesamum indicum) are the principal cash crops (Zougmoré 2003). ).
Extensive livestock production also plays an important role (cattle, small ruminants
andpoultry(INERA2006)).

11


Studyregion

Crop production particularly suffers from poor native soil quality, surface
crusting, low waterͲholding capacities, highly irregular rainfall patterns and high soil
andairtemperatures(BationoandBuerkert2001).Climatechangeprojectionsshowa
further increase in climate variability and adverse effects on crop yields (IPCC 2001;
World Bank 2013a). SmallͲscale agricultural systems are most vulnerable to these
changesinclimateduetotheirpooradaptivecapacity(IPCC2001;Mangoyana2009).
All in all, low agricultural productivity continues to impede poverty reduction.
Therefore, major governmental efforts target agricultural intensification through
mechanization, financial lending, water storage, crop diversification, and soil
restoration(Hanffetal.2011;WorldBank2013a).

2.4

Energyusepattern

Burkina Faso is facing a major energy crisis. More than 80% of the country’s energy
consumption is covered by traditionally used biomass such as fuel wood, dung and
cropresidues(Hanffetal.2011).Withitsgrowingpopulationanditsincreasingneed
for energy, the consumption of biomass exceeds the capacity of biomass reͲgrowth
(Bugaje 2006; Tatsidjodoung et al. 2012). Unsustainable use of biomass leads to soil
erosion and land degradation, which are becoming the most serious environmental
issues linked to energy consumption (Bugaje 2006; Toonen 2009; Sawe 2012).
Moreover, indoor air pollution from open cooking fires is estimated to cause 16,500
deaths per year (WHO 2004). The remaining national energy need is covered by
imported hydrocarbons used mainly for transportation and electricity production
(Tatsidjodoung et al. 2012). As net importer of fossil oil, amounting to 50% of the
nationaltradebalance,BurkinaFasoisheavilyaffectedbyrisingoilprices(Hanffetal.
2011;Tatsidjodoungetal.2012).
Overall,BurkinaFasohasaverylowlevelofenergyconsumption(234kgoe
per inhabitant compared with 1145 kgoe per inhabitant worldwide), and very poor

accesstoelectricity(<1%inruraland<15%inurbanareas)(Blinetal.2008;Hanffetal.
2011).Ithaslongbeenrecognizedthatenergypovertyisdirectlylinkedtoeconomic
poverty (Karekezi 2002; Bugaje 2006). Therefore, the country’s renewable energy

12


Studyregion

sourcesurgentlyhavetobeharnessed(e.g.,solarenergy,biogas,biofuel)inorderto
supplythegrowingdemandinenergytosupportthenation’sdevelopment,increase
the independency from imported fossil fuel, and reduce environmental degradation
andhealthimpactsassociatedwiththetraditionalbiomassuse(Karekezi2002;Bugaje
2006;Toonen2009,Hanffetal.2011).


13